Method for making electrically welded chain links



Jan. 12, 1937.

F. c. RAUWENHOFF METHOD FOR MAKING ELECTRICALLY WELDED CHAIN LINKS FiledAug. 24, 1955 .2 Sheets-Sheet l Jan. 12, 1937. F ENHFF 2,067,342

METHOD FOR MAKING ELECTRICALLY WELDED CHAIN LINKS Filed Aug. 24, 1935 2Sheets-Sheet 2 /v rank)" UNITED STATES-PATENT OFFICE A n'cnsm LINK lFrans Christiaan Rauwenhofl, OegstgeestLNetherlands, assignor toNaamloome Vennootsc Koninklijke Nederlandsche Grof'smederlj, Lei den,Nethex-lands, a corporation oi the Netherlands Application August 24,1935. Serial No. 37.755,

2 Claims. (01. ere-1o) The -rwction relates to a'method tor makinelectrically welded chain links by the hash welding system.

Methods are lsnown in which a link body is provided with a gap at oneside.

closure or filling piece is pressed by exerting a pressure upon itdirected perpendicularly to the plane of the link. During this pressingaction electrical welding current is' passed through and the fillingpiece is welded in the gap of the C- shaped link body. 9 r

The object" oi the invention is to vary. these known methods in such away that flash welding may be applied in order to secures. uniformheating and an entire contact ofth'suriaces to be welded. I I

.According to the invention a metal rod is initially bent in the shapeof a c and anelectric current is passed through the back'portion of theC-shaped rod to heat it. The filling piece being positioned in the gapbetween the ends of the C-shaped rod, the back of the latter is bent to"press the end faces thereof against the ends of said filling. piece.Welding current is now. applied to both ends of the c and to the fillingpiece,

the current applied toboth ends of the C-shaped rod having the samepolarity, differing from the v polarity of the filling piece.

This method. may be appliedfor making plainlinks as well as stud-links.In the latter case the filling piece has the shape of a T, the long legvof which constitutes the stud. The end thereof is electrically insulatedat the inner side .ofthe link, so that the welding current is com-'pelled to. take its way through the short leg oi the T, forming'thefilling proper in the gap. 'As

an insulating means various substances may be.

used such. for instance, as mica or a mixture of dextrine and chalk. Inparticular this latter substance has given good results in practice;

The invention will be more fully understood with reference to thepartially diagrammatic T drawings illustrating embodiments of links andserving to bend the link.

Fig. 5 shows the link after the welding and the 'deburrinz operation.

Figs. 6, and '1 illustrate two stages of the method.

. Fig. 8 shows the device f or, the bending ot then' link ends duringthe welding operation.

Fig.9 isasideelevationolthisdmce.

Into this gap at Fig. 10 shows a detail of the stud of afillingpiece-clamping-device.

In Fig. .1 the shape of the link body I is shown, -which shape isobtained by'bending a rod of round StEGIiOI the illustrated shape afterheating up to about 600U. in a hydrauliclbending machine. The portion ofthe link-back at la is straight as shown on the drawings. The 8Iid$ "2of the C obtained in this manner are, after the bending, sawed on in asawing machine in such a manner that the distance on between said endfaces is slightly larger than the length 12. oi a filling piece 3 (Fig.2) or t (Fig. 3) adapted to rill-up the opening. The filling pieces 3 ort are premoulded in dies.

material inthe stud head direction of the limit.

Thereafter. the bent link hody l' is clamped firmly with its bentportion in two clamps 5 and is in the longitudinal 6 of an electricalweldingmachineas schemati-v link body are simultaneously pressed againstthe ends of the stud piece 4 and while passing through the electricalcurrent are welded. The

'stud piece lremains stationary in the machineC It goes without sayingthat the successive links they are, brought into the welding machine orM before the stud piece or the filling piece is inserted. h K Afterwelding the burs are 'removed from the 1 welding spaces and the chain isannealed. H

. remarked above the welding is effected according to the flash weldingsystem. To this end the parts to be welded are initially pressed"against each other. Now; if the electrical current is passed through,thewelding-section 'or' area is heated. Asjsoon as a te'mperatureof pabout600 C. or 700 C. at the welding section or area'is attained therods are separated "from one another a distance of about 0.5 -1 mm. bycorre- .spondi'ngly moving the, clamps. 5 and 6. The current.- however;is still supplied and inthismanner an electrical arc is obtained. Theformation of thev arc may, of course, be repeated. The clamps are thenslowly moved towards one another and under an intense showeroi sparks vIt is remarked that when using stud pieces i the fibre-direction of theof a chain are hooked into one another before a portion of each rod (510mm., according to the circumstances) is melted off. This melting off iscontinued until the ends of the rods are white hot (11200 C.) whereafterthe two rods are rapidly and forcibly pressed against each other(so-called up-setting). The welding process is now terminated.

The link has then obtained the shape shown in Fig. 5 in which theinitially straight portion is of the back is also bent.

The main part'of the machine will now be.

described. I

In Fig. 6 the welding transformer and the clamping pieces have beenshown in the position they occupy during the heating of the back of theC, while Fig. 7 shows in what manner during the welding operation theelectrical tension is applied to the stud piece on the one hand and eachof the link ends on the other hand.

As already remarked the leg of the stud pieceis to this end electricallyinsulated with respect to the back of the C. The current is supplied ina manner to be explained hereinafter.

It follows from Figs. 4, 8, and 9 that the clamps I, 8 each comprise twopairs of parts. The parts of the clamps 5 are in pairs secured uponsleeves I, II, where the parts of the clamps. 8 are mounted upon sleeves8, I I. Rods 24, 25 attached to the sleeves 8, 8 are adapted to adjustsaid sleeves longitudinally and may be locked in position in accordancewith links of different size. The rods 28, 29 form piston rods in the.sleeves ll, Ii and are adapted to be pressed hydraulically by means ofa piston against the link ends in the direction indicated by arrows.

The sleeves are slidable between profile-irons l2, I! provided with armsII, II by means of which they may be swung with respect to each otherabout the'hollow pivots Ia of the brackets 20, 21. The arms I are bymeans of links II, II pivotally connected to the head of a red Itcarrying a piston is, which is slidable in a stationary hydrauliccylinderjll. The supply and discharge of the pressure medium determinesthe movement of the clamps 5, 6 about the pivots 1a and thereby thebending of the c. The sleeves l, 0, II, and II and pressure rods 2|, 2!,22, 22 partake in this movement.

Pressure rods 2|, 22 passing through the hollow pivot 1a areelectrically insulated with respect to the clamps and the machine frame.Between said rods the studpiece 4 (Fig. 3) is positioned in such amanner that the link portion 22 thereof is engaged (Figs. 10 and 4). Thecurrent thus needs only to takea very short path through the metal ofthe stud piece and the device is thereby also :dapted to operate withfilling pieces 2 18.

The rod 2| is stationary but adjustable. while the rod 22 is adapted tobe hydraulically pressed in the direction of the arrowin Fig. 9. whenthe clamps are rotated to bend the link ends the rods 2|, 22 are lockedagainst rotation, so that the stud piece will be positioned correctlymidway the link. The rods 2i, 22 are mounted in ball bearings. .The rods2|, 22 are located in the axis of retation of the device, whereas theclamping places (Fig. 10) are arranged eccentrically. By adjusting therods about their axes by means of an operating arm the place ofengagement of the part 23 of the stud piece or the filling piecerespectively may be altered. Seeing that all of the clamping andpressure pieces are under current and are movable or adjustable,'thecurrent,

is supplied thereto by non-shown U-shaped strips of sufllcient crosssectional area Which are resilient by reason of the fact that they aremade of copper-foil or are laminated so as to be composed of thinU-shaped elements. TheU-shaped elements or strips are rigidly connectedto other similar U-shaped strips, the curved portion of which is locatedin a plane making an angle, preferably a right angle, with the plane inwhich the curved portion of the first strip is located.

I claim:

1. A method for making electrically welded chain links by the flashwelding .system from metal rods initially bent in the shape of a c, andfilling pieces consisting in passing an electric current through theback portion of the C-shaped rod to heat the latter, positioning thefilling piece in the gap between theends of the c-shaped rod and bendingthe back of the latter to press the end faces thereof against the endsof said filling piece, and applying welding current to both ends of thec-shaped rod and to the filling piece, the current applied to both endsof the c-shaped rod having the same polarity diflering from the polarityof the filling piece, and electrically insulating said filling piecefrom the back of said C-shaped rod.

2. A method for making electrically welded chain links by the flashwelding system from metal rods initially bent in the shape of a C, andfilling pieces consisting in passing an electric current through theback portion of the c-shaped rod to heat the latter, positioning thefilling piece in the gap between the ends of the G-shaped rod andbending the back of the latter to press the end faces thereof againstthe ends of said filling piece, and applying welding current to bothends of the c shaped rod and to the filling piece, the current appliedto both ends ofthe c-shaped rod having the same polarity differing fromthe polarity of the filling piece.

FRANS CHRISTIAAN RAUWENHOFF.

